Intermittent preventive treatment against malaria: fresh hope for children
- Media list
Malaria kills one to three million people a year worldwide, most of them in tropical Africa. It is the foremost cause of infant death in the Sahelian zone, especially among under-fives, and increasing drug resistance is making this situation worse. New anti-malaria treatments and fresh approaches to preventing infection are badly needed.
In the Sahelian zone, malaria transmission is highly seasonal, with an annual peak towards the end of the rainy season: over 90% of annual malaria morbidity and mortality among under-fives occurs in a period of just three months. To prevent this annual peak, scientists from IRD research units UR 77 (Malaria research in tropical Africa) and UR 24 (Epidemiology and prevention), Cheikh Anta Diop University in Dakar and the London School of Hygiene and Tropical Medicine tested a new approach: seasonal intermittent preventive treatment. This consists of administering therapeutic doses of antimalaria drugs to children at fixed intervals.
While the WHO advises against conventional chemoprophylaxis in Africa because it is difficult to practice on a large scale and favours the spread of drug-resistant strains, intermittent preventive treatment has the advantage of keeping the number of drug doses to a minimum, administered on precise dates according to the seasonal transmission pattern. The idea is to step in just before the infection arrives, to achieve an optimum cost-efficiency ratio without augmenting the selection of drug resistant parasite strains.
The study was a random, double-blind, placebo-controlled trial involving 1,136 children aged between two months and five years living in the seasonal malaria transmission zone, in Niakhar, a rural area 150 km from Dakar. Once a month during the three-month peak period (September to November), half the children received a combination of the malaria drugs artenusate and sulfadoxine-pyrimethamine, and the other half received a placebo with no active ingredient. The treatment was administered without prior testing for malarial infection. The trial was funded by the Bill and Melinda Gates Foundation.
During the 13 weeks the children were monitored, only 39 episodes of malaria were recorded among the treated children, compared to 222 in the control group - a reduction of 86% in the number of malaria attacks. Tolerance to the drugs was excellent.
The results show that this new approach confers excellent protection against malaria in young children in the particular environment of the Sahel. These results in young children are especially promising because, with so few doses delivered, the cost of the operation is low despite the use of two malaria drugs in combination. This also makes it possible to apply the strategy on a large scale without risking rapid selection of drug-resistant parasite strains. A project involving 100,000 children should start in Senegal in late 2006, to assess the efficiency of this type of operation when run by the community.